Invisible Ink

Make your own invisible ink so you can write and reveal secret messages. Get information about inks that are activated by heat, chemical reactions, and ultraviolet light.

Learn how to make blue or red ink that will disappear after exposure to air. Tips for restoring the color and an explanation of the acid-base chemistry of the reaction are also included.

These are quick and easy instructions for making non-toxic invisible ink using baking soda (sodium bicarbonate).

The writing for this invisible ink technique is done using corn starch. An iodine solution is used to reveal the message.

Lemon juice is acidic and weakens paper. When paper is heated, the remaining acid turns the writing brown before discoloring the paper.

It's easy to write a message using invisible ink, but it's a little trickier to read the message. Here are tips for revealing an invisible ink secret message.